Global spatiotemporal consistency between meteorological and soil moisture drought indices

Date

2022-04-01

Author

Afshar, Mahdı Hesamı
Bulut, B.
Düzenli, Eren
Amjad, M.
Yılmaz, Mustafa Tuğrul

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

225
views

0
downloads

In this study, the consistency of a set of meteorological and soil moisture drought indices has been analyzed using the linear relationship between them. Commonly used Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) are compared to soil moisture drought index (SSMI) between the years 1981 and 2019. The most consistent meteorological drought index with SSMI has been selected as the best representative of it for 175,840 pixels, globally. Later, different classification methods (i.e., Decision Tree, K-Nearest Neighbors, Naïve Bayesian, Support Vector Machine, and Random Forest) are trained to identify the best representative of SSMI by considering the most consistent meteorological drought index with SSMI as target, and five ancillary datasets of average precipitation, average temperature, vegetation cover (Normalized difference vegetation index; NDVI), climate class, and land cover class as input variables of them, respectively. Results show that over 48% of pixels SPI, and over 32% of pixels SPEI show significantly better consistency with SSMI (at p-value: 0.05). Overall, in regions with cooler temperatures and low and high vegetation cover densities, the SPI, and over warmer areas with mid-range of vegetation density, the SPEI provides a better correlation with SSMI. The performance of different classification methods over validation pixels showed that the K-Nearest Neighbor method can identify the best correlated meteorological drought index with SSMI better than other methods. Overall results highlight the impact of climate and land use on interactions of meteorological and soil moisture drought indices, particularly that the classification efforts showed that, on average, monitoring of drought events by combine use of SPI and SPEI (each one over the area where it is identified as the best indicator of SSMI) improves the correlation between meteorological and soil moisture drought indices by 4 and 10%, compared to the uniform use of SPI and SPEI, respectively.

Subject Keywords

Agricultural drought, Classification, Soil moisture, SPEI, SPI, SSMI

URI

https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85123890964&origin=inward
https://hdl.handle.net/11511/95984

Journal

Agricultural and Forest Meteorology

DOI

https://doi.org/10.1016/j.agrformet.2022.108848

Collections

Department of Civil Engineering, Article

Suggestions

OpenMETU
Core

Remote sensing of canopy water content during SMEX'04 and SMEX'05 using shortwave-infrared reflectances Hunt Jr., E. Raymond; Yılmaz, Mustafa Tuğrul; Jackson, Thomas J. (2008-12-01) The Soil Moisture Experiments in 2004 and 2005 were conducted to validate algorithms for soil moisture retrievals. One of the key parameters for determination of soil moisture from microwave sensors is the vegetation water content of canopy and stems. We tested if canopy water content could be determined from reflectances in the shortwave-infrared and if the amount of canopy water content was related to the total vegetation water content by allometric equations. The normalized difference infrared index (NDI...
Thermal characterization and gasification kinetics of thrace-saray region coal Yıldırım, Betül; Kök, Mustafa Verşan; Department of Petroleum and Natural Gas Engineering (2015) In this thesis being up as-received and washed and dried, two different coal samples from Saray-Edirkoy field were experimented in order to determine effects of different variables as coal type, heating rate, gas flow rate, isothermal duration, gasifying medium, and final gasification temperature, on isothermal gasification profiles of the coal samples. In the scope of this study, heating rate was changed in the range of 20-50oC/min as 20, 30, 40 and 50oC/min whereas two different gas flow rate values as 60...
Obtaining soil-water characteristic curves by numerical modeling of drainage in particulate media / Shoarian Sattari, Amir; Toker, Nabi Kartal; Department of Civil Engineering (2014) The soil water characteristic curve (SWCC) reflects fundamental drainage properties of partially saturated soils by revealing the relation between soil suction and water content. Although during the past decades, various experimental methods have been proposed for obtaining the SWCC, these approaches are generally time consuming, expensive and highly dependent on operator skills. One solution to this has been sought through various empirical or physico-empirical formulations that link the SWCC to common soi...
Impacts of climatic variables on water-level variations in two shallow Eastern Mediterranean lakes Yagbasan, Ozlem; Yazıcıgil, Hasan; Demir, Vahdettin (2017-08-01) Variations in temperature and precipitation have direct impacts on the physical, chemical and biological characteristics of the shallow lakes. This paper examines the possible linkages between climate variables and the water levels of shallow interconnected Lakes Mogan and Eymir, located 20 km south of Ankara in Central Anatolia. The variations in the lakes' water levels during 1996-2015 are studied and the impacts of climate variables on the lake levels are assessed to address the long-term consequences. T...
Soil water content estimation from point scale to plot scale Demir, Gökben; Akyürek, Sevda Zuhal; Department of Civil Engineering (2018) Estimating soil moisture is crucial for understanding vadose zone and surface hydrology dynamics. In this study, soil moisture measurement is investigated by using a range of techniques spanning different spatial scales in a test basin in the south of Turkey. A cosmic ray sensor soil moisture probe (CRS) and a water content reflectometer (CS-616) have been installed for retrieving volumetric soil moisture data continuously. Lab analyses have been performed for calibrating the installed instruments and to ob...

Citation Formats

M. H. Afshar, B. Bulut, E. Düzenli, M. Amjad, and M. T. Yılmaz, “Global spatiotemporal consistency between meteorological and soil moisture drought indices,” Agricultural and Forest Meteorology, vol. 316, pp. 0–0, 2022, Accessed: 00, 2022. [Online]. Available: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85123890964&origin=inward.